The transfer characteristics of a base biased transistor has the operation regions, namely, cutoff, active region and saturation region. For using the transistor as an amplifier it has to operate in the

Options

A. active region
B. cutoff region
C. saturation region
D. cutoff and saturation

Explanation

To determine the correct operation region for using a base-biased transistor as an amplifier, we need to analyze the different regions of operation: cutoff, active, and saturation.

### Step-by-Step Solution:

1. **Understand the Regions of Operation**:
- **Cutoff Region**: In this region, the transistor is off, and no current flows through it. The input signal is too low to turn the transistor on.
- **Active Region**: In this region, the transistor is on and can amplify signals. It allows for a linear relationship between the input and output, making it suitable for amplification.
- **Saturation Region**: In this region, the transistor is fully on, and it acts like a closed switch. While it can conduct a large current, it does not amplify the signal.

2. **Identify the Purpose of the Transistor**:
- For amplification, we need the transistor to respond to changes in the input signal and produce a larger output signal. This requires a linear relationship between the input and output.

3. **Determine the Suitable Region for Amplification**:
- The **active region** is where the transistor can amplify signals. In this region, the transistor can provide current gain, power gain, and voltage gain, which are essential for amplification.

4. **Conclusion**:
- Therefore, to use the transistor as an amplifier, it must operate in the **active region**.

### Final Answer:
For using the transistor as an amplifier, it has to operate in the **active region**.

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